1. Field of the Invention
The present invention relates to a three dimensional measuring apparatus which measures the shape of a press mold, manufactured by applying CAD/CAM methods, by means of a pair of CCD cameras and a laser scanner for example.
2. Background of the Invention
For example, any of the conventional press molds, needed for manufacturing automotive bodies, is manufactured by executing sequential processes including the following: Initially, based on data from processes for designing body style, body structure, and press mold, the design staff prepare a variety of numerically controllable data needed for manufacturing press molds by operating NC machine tools. Next, prepared numerically controlled data are stored in NC machine tools before eventually producing the predetermined press molds by operating the NC machine tools.
Next, each press mold, formed by the NC machine tools, is delivered to a finish-up process, where actual dimensions of the formed press mold are measured by operating a measuring apparatus. In order that the measured value can correctly match the predetermined design value, using a grindstone and a sandpaper, an operator manually grinds the surface of the formed press mold to complete the whole manufacturing processes.
Nevertheless, according to the existing method of manufacturing press molds described above, in particular, on the way of finally finishing up each press mold, the operator needs to mount an unfinished press mold on a measuring apparatus at the measuring position. Next, the operator measures actual of the unfinished press mold, and then again sets it to a predetermined finish-up position before eventually finishing up the processed press mold by referring to the measured values.
Nevertheless, the result of the measurement yielded from the existing measuring apparatus is not directly shown on the mounted press mold, but instead, the measured values are displayed on a CRT for example. Therefore, the operator can merely identify a faulty location of the mounted press mold containing an error solely by monitoring the CRT display before eventually finishing up the processed press mold. In other words, potential error can be generated from the final finish-up process.
Furthermore, the operator cannot measure the actual dimensions of the processed press mold while executing the final finishing process by applying any conventional measuring apparatus. Therefore, after completing the final finishing process, the operator needs to again mount the finished press mold on the measuring apparatus to check and confirm whether the finishing process has correctly been executed, or not. In consequence, while the final finishing process is underway, the operator needs to reciprocate the processed press mold between the measuring position and the finishing position several times, thus extremely complicating the final finishing process.